1. Field of Invention
The present invention relates to a thermostat that the reactivity thereof is improved and changes a passage of a coolant depending on the temperature of the coolant and actively controls the coolant temperature to prevent the overheating thereof.
2. Description of Related Art
A thermostat for a vehicle is disposed between an engine and a radiator and is opened/closed in response to the temperature variation of coolant to adjust the flow rate of the coolant, and therefore the temperature of the coolant is controlled in a predetermined range.
A mechanical thermostat expands wax depending on the temperature of the coolant, and the expanding force of the wax makes a piston move the valve of the thermostat.
The mechanical thermostat is operated in response to a predetermined opening/closing temperature of the coolant to open/close the valve only in a predetermined temperature condition, and therefore the mechanical thermostat does not actively move against changes of the driving circumstances of the vehicle.
Accordingly, an electrical thermostat has been introduced to complements the drawback of the mechanical thermostat, and the electrical thermostat is operated to sustain the coolant temperature in an optimized range.
The electrical thermostat actively controls the coolant temperature of the engine according to the driving circumstances such as the load level of the vehicle to sustain the optimized coolant temperature, and the electrical thermostat can improve fuel consumption efficiency and reduce exhaust gas.
Meanwhile, when a first valve is closed in a thermostat, the coolant that is supplied through a second passage flows around a wax case that is disposed in a valve guide and wax that is charged in the wax case is contracted or expanded.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.